The present invention relates to composite materials, in particular to light-transforming materials used in agriculture, medicine, biotechnology and light industry.
An object of the invention is to provide a light-transforming material capable of converting UV light into red light and retaining this capability for a long period.
This issue became urgent especially first because of the necessity to protect humans, animals and plants against solar UV radiation as well as against technogenic UV radiation (UV radiation) which, as known, causes skin solar burns and stimulates to the development of oncology diseases including skin melanoma. Secondly, many publications describe favorable effect of the red light, which enhances the activity of catalase, superoxide dismutase and glutathione reductase enzymes (Y. A. Vladimirov et al., xe2x80x9cFree Radical Biol. Med.xe2x80x9d, N5. 1988, p.281-286), that, in turn, decreases the amount of active forms of oxygen that damages the cell, and also intensifies DNA and protein synthesis (T. I. Karu xe2x80x9cPhotobiology of low-power laser therapyxe2x80x9d in V. S. Letokhov et al. xe2x80x9cLaser Science and Technologyxe2x80x9d. Harwood Academic Publishers, Chur, Switzerland, 1989), that in turn promotes healing of wounds, and recovery of skin from solar burns. In addition, red radiation (wavelength 600-630 nm) is absorbed most efficiently by chlorophyll-b of a green leaf. Hence, photosynthesis runs faster, green weight of plants grows harvest of greenhouse cultures increases and the period of ripening becomes shorter (Stoy V., Physiol. % and a mPlant., 1955, v. 18, p.963-986; Inada K., Plant and cell physiol., 1976, v.17 p. 355-365; GB 2158833).
Materials are known which contain a matrix and an active additive capable of absorbing UV-radiation (U.S. Pat. No. 4,081,300; JP 53-136050; JP A3-158103 published on Aug. 08, 1991; FR 2419955), or capable of providing proportioned UV-emission (WO 94/17135). As an active additive, the material comprises carbon black and phthalocyanine dyes (JP 53-136050), benzophenone or benzotriazole (FR 2419955), n-t-butyl(phenyl)salicylate or 2-hydroxy-4-metoxybenzophenone (JP A3-158103), the compounds of salicylic, citric and oxalic acids in combination with dyes, e.g. blue or violet (WO 94/17135). The matrix is extruded into the film of thermoplastic polymers (U.S. Pat. No. 4,081,300, JP 53-136050, FR 2419955), or is made of fibrous material (natural or synthetic) (JP A3-158103), or made in the form of plates of thermoplastic polymers (WO 94/17135), or made of nonfibrous material, thread or lacquer (WO 94/17135). A film-like material is intended to be mostly used in agriculture to protect greenhouses and hothouses (U.S. Pat. No. 4,081,300, JP 53-136050, FR 2419955). A textile-like material is designed to be applied while manufacturing roof hoods and awnings (JP A3-158103), and a plate-like material is intended to be employed in making roof hoods, awnings and even roof overlays (WO 94/17135).
Nevertheless, all these material are unable to transform the UV-light into the red light.
A light-transforming material (CH 667463, GB 2158833) is known which contains a matrix and at least one coordination compound of rare-earth metals (europium, samarium, terbium, gadolinium), as an active additive, which provides transformation of UV component of the light into the orange-red spectral range (580-750 nm). The matrix is extruded into the film of thermoplastic polymer. The composition for the production of this material contains an active additivexe2x80x940.001-5.0 wt. % and a matrix-forming componentxe2x80x9495.0-99.99 wt. %. As the matrix-forming component, the composition contains at least one polymer, selected from the group consisting of polyethylene, polypropylene, polyvinyl chloride, polycarbonate (PC), polystyrene, polymethyl methacrylate or their copolymers. This material retains its light-transforming activity for no more than 60 days as the compounds of rare-earth metals used for the production of this material refer to coordination compounds, which can be quickly decomposed under the action of light.
A light-transforming material (RU 2059999) is known which contains a matrix and at least one composite compound, as an active additive, of the general formula [(La1xe2x88x92xEux)O]m(Lig)n, where Lig is F, Cl, Br, O, S, or Se, which could also transform UV component of light into the orange-red spectral range (580-750 nm). This material is made in the form of film of thermoplastic polymer. The composition for the production of this material contains an active additive, 0.05-1.0 wt. % and a matrix-forming agent, 99.0-99.95 wt. %. The composition contains at least one polymer, as a matrix-producing agent, selected from the group consisting of polyethylene, copolymers of polyethylene and vinyl acetate (EVA) or poly(ethylene terephthalate).
This material is also capable of converting UV component of a spectrum of light source to the red light. This material retains its activity only for no more than 300 days since all oxohalogenides and especially oxoselenides of rare-earth compounds are decomposed in the air and, in particular, in the presence of moisture.
The main object of the present invention is to prolong the capability of the light-transforming material to convert UV-light into red light under the same intensity of this conversion by enhancing the resistance of an active additive to the action of light, air and moisture.
An other object is to enlarge the arsenal of the substances suitable for manufacturing materials with light-transforming capability.
One more object is to increase the heat-protecting capability of the material.
The foregoing objects of the present invention are achieved by offering the production of the light-transforming material containing a matrix and an active additive converting the UV-light into the orange-red spectral range. In accordance with the invention, as an active additive, this material contains apatite and at least one europium (III) composite compound of the general formula MexmEuy3Rzn, or a mixture thereof with at least one composite compound of either samarium (III), terbium (III), or gadolinium (III), with the general formula for each:
MexmMy3Rzn,
wherein mx+3y=nz,
Mexm=Mexxe2x80x2mxe2x80x2+Mexxe2x80x3mxe2x80x3+ . . . ,
Rzn=Rzxe2x80x2nxe2x80x2+Rzxe2x80x3nxe2x80x3+ . . . ,
mx=mxe2x80x2xxe2x80x2+mxe2x80x3xxe2x80x3+ . . . ,
nz=nxe2x80x2zxe2x80x2+nxe2x80x3zxe2x80x3+ . . . ,
xxe2x89xa71.0xe2x89xa7yxe2x89xa70.01,
Me represents a metal selected from the group consisting of yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, ytterbium, aluminium, bismuth, tin, titanium, manganese, calcium, barium, zinc, cadmium, sodium, potassium, rubidium and cesium;
M represents a metal selected from the group consisting of europium, samarium, terbium and gadolinium;
R represents a member selected from the group consisting of oxygen, sulfur, fluorine, chlorine, bromine, phosphorus, boron, vanadium, molybdenum, tungsten, germanium, or a combination thereof; and
m and n are the charge of a Me or R ion, respectively.
Herein, the active additive can be distributed inside or over the surface of the matrix.
The material contains an active additive in amounts of at least 0.02 wt. % of the material.
The matrix is made light-transparent.
As apatite, the material comprises natural or synthetic apatite having a crystalline lattice in a finely divided condition, corresponding to the formula Ca10(PO4)6Rxe2x80x22 (where Rxe2x80x2xe2x80x94F, Cl or OH), or their mixture in any proportions.
The composite compound contains, at least, one composite compound wherein nz=3, Rxe2x80x94O, Gal of the formula MexMyOGal, Gal is F, Cl, Br; or wherein nz=6, R=O, Hal of the formula MexMyO2Hal, Hal is S or Se; or of the formula MexMyO2S1xc2x10,2; or wherein nz=6, R=VO4 of the formula MexMy(VO4)2; or wherein Rxe2x80x94BO3, PO4 of the formula MexMy(BO3)zxe2x80x2(PO4)zxe2x80x3; or wherein Rxe2x80x94VO4, PO4 of the formula MexMy(VO4)zxe2x80x2(PO4)zxe2x80x3; or wherein Rxe2x80x94VO4, PO4, BO3 of the formula MexMy(VO4)zxe2x80x2(PO4)zxe2x80x3(BO3)zxe2x80x3; or wherein Rxe2x80x94BO2, WO4, MoO4 of the formula MexMy(BO2)zxe2x80x2(WO4)zxe2x80x3; or MexMy(BO2)zxe2x80x2(MoO4)zxe2x80x3; or the mixture of compounds thereof.
Thus, as a compound of the general formula MexMyOGal or MexMyO2Hal, the material comprises the product of processing of solid solutions of Me and M oxides in a medium of alkaline halogenides or halkogenides at 800-1200xc2x0 C.; as a compound of the general formula MexMyO2S1xc2x10,2, the material comprises the product of processing of Me and M oxides in sulfurous medium at 1200xc2x0 C.; as a compound of the general formula MexMy(VO4)2, the material comprises the product of interaction of the solid-phase Me and M oxides with ammonium vanadate at 900-1100xc2x0 C.; as a compound of the general formula MexMy(BO3)zxe2x80x2(PO4)zxe2x80x3, the material contains the product of interaction of the solid-phase Me and M oxides with boric acid and ammonium phosphate at 900-1100xc2x0 C.; as a compound of the general formula MexMy(VO4)zxe2x80x2(PO4)zxe2x80x3, the material comprises the product-of interaction the solid-phase Me and M metal oxides with vanadate and ammonia phosphate at 1000-1200xc2x0 C.; as a compound of the general formula MexMy(VO4)zxe2x80x2(PO4)zxe2x80x3(BO3)zxe2x80x2xe2x80x3, the material contains the product of interaction of the solid-phase Me and M oxides with vanadate and ammonium phosphate as well as boric acid at 800-1100xc2x0 C.; as a compound of the general formula MexMy(BO2)zxe2x80x2(MoO4)zxe2x80x3; or MexMy(BO2)zxe2x80x2(MoO4)zxe2x80x2, the material comprises the product of interaction of the solid-phase Me and M oxides, tungsten (molybdenum) and boric acid at 1100-1200xc2x0 C.
The material can comprise in addition, at least, one coordination compound of metal E, selected from the group consisting of [E(TTA)3(Phen)], [E(TTA)3(TPhPO)2], (DPhG)H[E(TTA)4], (DPhG)H[E(HFAA)4], [E(HFAA)3(Phen)], [E(HFAA)3(TPhPO)2], (DPhG)H[E4(AA)4], [E(AA)3(Phen)], [E(BB)3(Phen)], [E(TFA)3(Phen)], (DPhG)H[E(TFA)4], [E(Capr)3(Phen)], [E2(Ter)3(Phen)2], [E(NO3)3(Phen)2], E represents a metal selected from group consisting of europium, samarium, terbium, and gadolinium; H represents hydrogen ion; TTA represents thenoyltrifluoroacetonato-anion, HFAA represents hexafluoroacetylacetonato-anion, BB represents benzoylbenzoato-anion, AA represents acetylacetonato-anion, TFA represents trifluoroacetato-anion, Capr represents capronato-anion. Ter represents terephtalato-anion, Phen represents 1.10-phenantrolyne, TPhPO represents triphenylphosphine oxide, DPhG represents diphenylguanidine.
As a coordination compound of metal E, the material can comprise the product of transformation of europium (II), samarium (III), terbium (III) or gadolinium (III) nitrate and thenoyltriflouracetone, hexafluoracetylacetone, or acetylacetone, benzoylbenzoic or trifluoroacetic, caproic, or terephthalic acid and 1,10-phenantroline, or triphenylphosphine oxide, or diphenylguanidine in aqueous-alcoholic medium at 80-90xc2x0 C.
The material can contain a matrix in the form of film, plate, or cloth textile or non-fibrous/fibrous material.
The matrix can be made of thermoplastic polymers.
The matrix can be made of soluble polymers.
The matrix can be made of polyester selected from the group consisting of polymethyl methacrylate, polybutylmethacrylate, polycarbonate(PC), poly(ethylene terephthalate) and their derivatives, or polyolefin selected from the group consisting of polypropylene, polyvinylchloride, polystyrene, polyethylene and their derivatives, polyamide or its derivatives; or copolymer of these polymers, or mixtures of these polymers.
The matrix can be made of fibrous material (natural including cotton, silk, wool, hemp, and their mixtures or synthetic including viscose, acetate, capron, nylon, polyamide, polyester, their copolymer, and their mixture, or a blend hereof), or a mixture of fibrous material thereof.
The matrix can be made of silicate or a modified silicate glass.
The matrix can be made of organic glass.
The material can comprise in addition lacquer or adhesive.
As lacquer or adhesive, the material can contain a silicone, polyester, polyepoxy, epoxy resin or a mixture thereof.
The objects outlined are also achieved by offering the composition for producing a light-transforming material with the involvement of a matrix-forming agent and an active additive. As an active additive, the composition contains apatite and at least one europium (III) composite compound of the general formula MexmEuy3Rzn, or a mixture thereof, at least with one composite compound of samarium (III), terbium (III), or gadolinium (III), with the general formula for each:
MexmMy3Rzn,
wherein mx30 3y=nz,
Mexm=Mexxe2x80x2mxe2x80x2+Mexxe2x80x3mxe2x80x3+ . . . ,
Rzn=Rzxe2x80x2nxe2x80x2+Rzxe2x80x3nxe2x80x3+ . . . ,
mx=mxe2x80x2xxe2x80x2+mxe2x80x3xxe2x80x3+ . . . ,
nz=nxe2x80x2zxe2x80x2+nxe2x80x3zxe2x80x3+ . . . ,
xxe2x89xa71.0xe2x89xa7yxe2x89xa70.01,
where Me represents a metal selected from the group consisting of yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysprosium, holmium, erbium, ytterbium, aluminium, bismuth, tin, titanium, manganese, calcium, barium, zinc, cadmium, sodium, potassium, rubidium, and cesium;
M represents the metal selected from the group consisting of europium, samarium, terbium, gadolinium;
R represents an element selected from the group consisting of oxygen, sulfur, fluorine, chlorine, bromine, phosphorus, boron, vanadium, molybdenum, tungsten, and germanium, or compounds thereof, and
m and n are the charge of a Me or R ion, respectively.
As a matrix-forming agent, this composition comprises a thermoplastic or soluble polymer, or fibrous material (natural, synthetic, or mixed ), or the composition for the production of organic, silicate, or a modified silicate glass or lacquer/adhesive-forming substance, in the following proportion of the components (wt. %):
The composition can contain in addition, at least one coordination compound of metal E, selected from the group consisting of:
[E(TTA)3(Phen)], [E(TTA)3(TPhPO)2], (DPhG)H[E(TTA)4], (DPhG)H[E(HFAA)4], [E(HFAA)3(Phen)], [E(HFAA)3(TPhPO)2], (DPhG)H[E4(AA)4][E(AA)3(Phen)], [E(BB)3(Phen)], [E(TFA)3(Phen)], (DPhG)H[E(TFA)4], [E(Capr)3(Phen)], [E2(Ter)3(Phen)2], [E(NO3)3(Phen)2] in the following proportion of the components (wt. %)
As the matrix-forming agent, the composition can contain polymer selected from the group consisting of poly(methyl methacrylate), polybutylmethacrylate, polycarbonate (PC), poly(ethylene terephthalate), polypropylene, polyvinyl chloride, polystyrene, polyethylene, polyamide, derivatives of these polymers, copolymer of these polymers, or the mixture of polymers thereof.
As a matrix-forming agent, the composition can also contain a composition for producing silicate or a modified silicate glass.
As lacquer/adhesive-forming agent, the composition can contain a silicone, polyester, polyepoxy, epoxy resin or their mixture.
As a natural fibrous material, the composition can contain fiber selected from the group consisting of silk, wool, cotton, hemp or their mixture.
As a synthetic fibrous material, the composition can contain fiber selected from the group consisting of viscose, acetate, polyester, polyamide, polyacrylamide or their mixture.
To clarify the essence of the present invention we consider the general formula of composite compounds of rare-earth metalsxe2x80x94phosphors, as an additive, and included into the material offered:
MexmMy3Rzn,
wherein mx+3y=nz,
Mexm=Mexxe2x80x2mxe2x80x2+Mexxe2x80x3mxe2x80x3+ . . . ,
Rzn=Rzxe2x80x2nxe2x80x2+Rzxe2x80x3nxe2x80x3+ . . . ,
mx=mxe2x80x2xxe2x80x2+mxe2x80x3xxe2x80x3+ . . . ,
nz=nxe2x80x2zxe2x80x2+nxe2x80x3zxe2x80x3+ . . . ,
xxe2x89xa71.0xe2x89xa7yxe2x89xa70.01
m and n are the charge of a Me or R ion, respectively.
This formula reflects a structure of composite compound including the ion-activatorxe2x80x94Me, fluorescent centerxe2x80x94ion M, and also an anionic part of the compoundxe2x80x94R, which compensate a positive charge of Me and M, where m and n are the charge of a Me and R ion, respectively.
It is necessary to point out that the composite compounds, offered as active additives, are heteropolynuclear complexes, where ion-activatorxe2x80x94Me and fluorescent centerxe2x80x94M interacts via bridge groupsxe2x80x94R. The latter gives rise a concept of xe2x80x9csolid solutionsxe2x80x9d, as just in solid solutions the formation of heteropolynuclear compounds is most possible.
As found (E. F. Kustov, G. A. Bandarkin, E. N. Muravyov, V. P. Orlovsky. xe2x80x9cElectronic spectra of rare earth compoundsxe2x80x9d Ed. By I. V. Tananayev, Science Moscow, 1981, p. 183), heteropolynuclear compounds containing europium (III), provide the brightest fluorescence in the area of 610-630 nm (the most important area for luminescent emission in the red spectral range). Therefore, the formula, which describes an element structure of compounds, offered as an active additive, includes, at least, two types of atomsxe2x80x94Me and M with indices x and y when restricting value xxe2x89xa71.0xe2x89xa7yxe2x89xa70.01, where M should be, at least, Eu (III).
The necessary condition of suitability of composite compound in object decision-making is the presence of europium (III) ions in it. The minor role is played by compounds of samarium (III), terbium (III), and gadolinium (III).
The ranges of values x and y are determined by the minimum value y=0.01, since when the content of fluorescent center M is less, transformation of UV-radiation is gentle; from experience, the value x=1.0 is minimum.
The anionic part of composite compounds in the formula represented is integrated with the value Rzxe2x80x2, that can include anions of a various structure and in different proportions: Rzxe2x80x2+Rzxe2x80x3+Rzxe2x80x2xe2x80x3. . . + . . .  wherein z=zxe2x80x2+zxe2x80x3+zxe2x80x2xe2x80x3+ . . .
For instance, the structure of the known composite compoundxe2x80x94phosphor of yttrium-europium vanadate phosphate is described by the formula YxEuy(PO4)(VO4), where:
Mexe2x80x94Yx3, Mxe2x80x94Euy3.R=(PO4)13xe2x88x92+(VO4)13xe2x88x92;
nz=1xc3x973+1xc3x973=6;
wherein x=1.9 mx=3xc3x971.9=5.7;
y=0.1, 3y=3xc3x970.1=0.3, hence, mx+3y=5.7+0.3=6.
The situation is also the same for the compound with formula Ba(Gd)1,9Eu0,1(WO4)4 where:
Mexm=Mexxe2x80x2mxe2x80x2+Mexxe2x80x3mxe2x80x3=Ba12+Gd1,93, My=Eu0,13, (WO4)42;
z=4, n=2, nz=4xc3x972=8;
wherein xxe2x80x2=1, xxe2x80x3=1.9, mxe2x80x2=1.0, mxe2x80x3=3.0;
mx=mxe2x80x2xxe2x80x2+mxe2x80x3xxe2x80x3=2xc3x971+3xc3x971.9=2+5.7=5.7;
wherein y=0.1, 3y=3xc3x970.1=0.3, hence mx+3y=7.7+0.3=8.0 and, therefore, mx+3y=nz.
Thus, the proposed formula of heteropolynuclear compounds appears to be most complete for the description of compounds (phosphors) structure among those we selected to achieve our technical outcome.
As found experimentally, the use of apatite (natural or synthetic with mean grain composition of 4-5 xcexcm) as an active additive, on the one hand, retains for a long period a fluorescence capability of composite compounds included in a structure of a light-transforming material, and on the other hand, enhances heat-particular features of the material, reinforces it and prolongs its service.
In addition, we revealed that combination of apatite and composite compound promotes an increased emission power in green and cyan spectral range.
The (heteropolynuclear) compounds of europium (III), samarium (III), terbium (III) and gadolinium (III), obtained by the method of solid-phase high-temperature synthesis, are thermally rather stable. Combination with natural or synthetic apatite makes these compounds suitable to be included in a structure of high melting organic polymers, for instance, poly(ethylene terephthalate) or polycarbonate (PC).
Coordination compounds of europium (III), samarium (III), terbium (III), and gadolinium (III) are used as extra component of an active additive since they provide bright luminescence in the green and orange-red spectral range, are soluble in a polymer (with the exception of nitrates and terephtalate) and, due to absorbing the UV-component of a sunlight they promote the prolonged action of composite compoundxe2x80x94phosphor.
The necessary and sufficient content of apatite, composite compound and coordination compound of rare earths in the material proposed is selected experimentally.
The content of apatite and composite compound in the material less than 0.01 wt. % of each additive is found to be unefficient, since no technical outcome is achieved. An increase of their concentration up to more than 10.0 wt. % of each accompanies an increased absorption of solar radiation in the material, indistinct transparency of the material if it is light-transparent, and also excessive consumption of active additive without the retaining of light-transforming capability for longer period in the material. Only combination of the said particular features leads to the accomplishment of the object outlined, namely to the prolonged light-transforming capability of the material to convert the UV-light into red light and reinforced heat properties of the material under the same intensity of converting UV-emission into red spectral range.
It is necessary to point out, that a selection of a matrix-forming agent for the production of the material proposed depends upon the field of application of the product made of this material. For instance, if the material is intended to be used for hothouses and greenhouses covering, it is obvious that a matrix should be light-transparent extruded into the film. Here, any known thermoplastic or soluble film-forming polymer, for instance, polymethylmethacrylate, polybutylmethacrylate, polycarbonate (PC), poly(ethylene terephthalate), polypropylene, polyvinylchloride, polystyrene, polyethylene, or polyamide could be used as a matrix-forming agent. The thermoplastic polymer, as a matrix-forming agent, can be used for obtaining a light-transforming material to produce biotechnological equipment, as for instance, Petri dish, test tubes, separating flasks, capillary tubes for cultivation of microorganisms and cell cultures, as well as to produce plates for winter greenhouse protection, fixed solariums and buildings for animals.
The composition for obtaining silicate (or other) glass, as a matrix-forming agent, can be used when the material proposed is intended to be applied, for instance, to glaze houses and office buildings, as well as greenhouses and buildings for animals, or for instance, to make glasses, automobiles, sun-visors and awnings.
Natural and/or synthetic fibers, as a matrix-forming agent, can be employed for obtaining light-transforming textile cloths required for instance, for manufacturing light-protective roof hoods and awnings, and also for producing light-protective clothes. Using artificial and, in particular, synthetic fibres, it is possible to make light-transforming bonded fabric and use it as a protecting material in agriculture.
Apatite (natural or synthetic), europium composite compound and a matrix-forming agent suitable for further application are used to produce the material offered.
As a natural apatite, it is more expedient to use colorless fine-crystalline apatite with mean grain composition of 4-5 xcexcm.
The process of obtaining a synthetic apatite is known and is described in the detail in literature (the method of production of fluoroapatite and hydroxyapatite is described by Yu. K. Voron""ko, A. V. Gorbachov, A. A. Zverev, A. A. Sobol"", N. N. Morozov, E. N. Murav""ev, Sh. A. Niyazov and V. P. Orlovskii in the article entitled xe2x80x9cRaman Scattering and Luminescence Spectra of Compounds with the Structure of Apatite Ca5(PO4)3F and Ca5(PO4)3OH. Activated with Eu3+Jons.xe2x80x9d Inorganic Materials. 1992, v. 28,1 3, p. 442; and by G. V. Rodicheva, V. P. Orlovskii, N. M. Romanova, A. V. Steblevskii, G. E. Sukhanova. Physicochemical Investigation of an Khibini Apatite and Its Comparison to Hydroxyapatite. Russian Journal of Inorganic Chemistry, 1996, v. 41,1 5, p. 728; and the obtaining of hydroxyapatite is described by V. P. Orlovskii, Zh. A. Ezova, G. V. Rodicheva, E. M. Koval, G. E. Sukhanova, in their article entitled xe2x80x9cConditions for the formation of hydroxyapatite CaCl2(NH4)2HPO4xe2x80x94NH4OHxe2x80x94H2O system (25xc2x0 C.),xe2x80x9d Russian Journal of Inorganic Chemistry, 1992, v. 37,1 4, p. 443).
The method of obtaining composite compounds as a component of an active additive, is also known (I. A. Bondar et al., xe2x80x9cCompounds of rare earth elements, silicates, germanates, phosphates, arsenates, vanadatesxe2x80x9d series xe2x80x9cChemistry of rare elementsxe2x80x9d, Ed. by I. V. Tananayev, Science, Moscow, 1983, p. 254-257).
The methods of obtaining coordination compounds of europium, samarium, terbium and gadolinium are known and described by L. R. Melby, N. J. Rose, E. Abramson, J. C. Caris, in their article xe2x80x9cSynthesis and Fluorescence of some Trivalent Lanthanide Complexesxe2x80x9d. J. Amer. Chem. Soc., 1964, v. 86, 23. p.5117.
The composite compounds, as a component of an active additive, are obtained by the conventional method of high-temperature synthesis (E. F. Kustov, G. A. Bandarkin, E. N. Muraviov, V. P. Orlovsky, xe2x80x9cElectronic spectra of compounds of rare-earth elementsxe2x80x9d Ed. by I. V. Tananayev. xe2x80x9cSciencexe2x80x9d, Moscow, 1981). In accordance with this method, the oxides of europium (III), samarium (III), terbium (III), or gadolinium (III) in combination with the oxide of yttrium (III) (or other metal), are mixed with corresponding components which form an anionic part (R) of the compound, and stand at 1100-1200xc2x0 C. for several hours. A clinker obtained in this way is then washed, dried and milled.